YYXC_Student/jiaPei/Category/UIImage+RQExtension.m

//
//  UIImage+RQExtension.m
//  test23
//
//  Created by apple on 15/12/1.
//  Copyright (c) 2015年 JCZ. All rights reserved.
//

#import "UIImage+RQExtension.h"

@implementation UIImage(RQExtension)

//将JPEG格式转换为PNG
-(UIImage *)reduceImage:(UIImage *)image percent:(float)percent
{
    NSData *imageData = UIImageJPEGRepresentation(image, percent);
    UIImage *newImage = [UIImage imageWithData:imageData];
    return newImage;
}
//压缩图片尺寸
- (UIImage *)scaledToSize:(CGSize)newSize
{
    //首先要找到缩放比 按长的适配 不足的部分空白
    CGFloat rate =newSize.width*1.0/ self.size.width ;
    if (self.size.height* rate > newSize.height) {
        //过长了。
        rate =newSize.height*1.0/ self.size.height ;
    }
    CGSize size = CGSizeMake(self.size.width*rate, self.size.height*rate);
    
    // Create a graphics image context
    UIGraphicsBeginImageContext(size);
    // new size
    [self drawInRect:CGRectMake(0,0,size.width,size.height)];
    // Get the new image from the context
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // End the context
    UIGraphicsEndImageContext();
    // Return the new image.
    return newImage;
}

- (UIImage *)scaledAndCutToSize:(CGSize)newSize{
    
    //首先要找到缩放比 按短的适配 长的部分裁减掉
    CGFloat rate =newSize.width*1.0/ self.size.width ;
    if (self.size.height* rate < newSize.height) {
        //过长了。
        rate =newSize.height*1.0/ self.size.height ;
    }
    CGSize size = CGSizeMake(self.size.width*rate, self.size.height*rate);
    
    UIGraphicsBeginImageContext(size);
    
    [self drawInRect:CGRectMake(0,0,size.width,size.height)];
    // Get the new image from the context
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // End the context
    UIGraphicsEndImageContext();
    // Return the new image.
    return newImage;
}

- (UIImage*)imageRotatedByDegrees:(CGFloat)degrees
{
    
    CGFloat width = CGImageGetWidth(self.CGImage);
    CGFloat height = CGImageGetHeight(self.CGImage);
    
    CGSize rotatedSize;
    
    rotatedSize.width = width;
    rotatedSize.height = height;
    
    UIGraphicsBeginImageContext(rotatedSize);
    CGContextRef bitmap = UIGraphicsGetCurrentContext();
    CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);
    CGContextRotateCTM(bitmap, degrees * M_PI / 180);
    CGContextRotateCTM(bitmap, M_PI);
    CGContextScaleCTM(bitmap, -1.0, 1.0);
    CGContextDrawImage(bitmap, CGRectMake(-rotatedSize.width/2, -rotatedSize.height/2, rotatedSize.width, rotatedSize.height), self.CGImage);
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

+ (UIImage *)fixOrientation:(UIImage *)image {
	// No-op if the orientation is already correct
	if (image.imageOrientation == UIImageOrientationUp) return image;
	
	// We need to calculate the proper transformation to make the image upright.
	// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
	CGAffineTransform transform = CGAffineTransformIdentity;
	
	switch (image.imageOrientation) {
		case UIImageOrientationDown:
		case UIImageOrientationDownMirrored:
			transform = CGAffineTransformTranslate(transform, image.size.width, image.size.height);
			transform = CGAffineTransformRotate(transform, M_PI);
			break;
			
		case UIImageOrientationLeft:
		case UIImageOrientationLeftMirrored:
			transform = CGAffineTransformTranslate(transform, image.size.width, 0);
			transform = CGAffineTransformRotate(transform, M_PI_2);
			break;
			
		case UIImageOrientationRight:
		case UIImageOrientationRightMirrored:
			transform = CGAffineTransformTranslate(transform, 0, image.size.height);
			transform = CGAffineTransformRotate(transform, -M_PI_2);
			break;
			
		default:
			break;
	}
	
	switch (image.imageOrientation) {
		case UIImageOrientationUpMirrored:
		case UIImageOrientationDownMirrored:
			transform = CGAffineTransformTranslate(transform, image.size.width, 0);
			transform = CGAffineTransformScale(transform, -1, 1);
			break;
			
		case UIImageOrientationLeftMirrored:
		case UIImageOrientationRightMirrored:
			transform = CGAffineTransformTranslate(transform, image.size.height, 0);
			transform = CGAffineTransformScale(transform, -1, 1);
			break;
			
		default:
			break;
	}
	
	// Now we draw the underlying CGImage into a new context, applying the transform
	// calculated above.
	CGContextRef ctx = CGBitmapContextCreate(NULL, image.size.width, image.size.height,
											 CGImageGetBitsPerComponent(image.CGImage), 0,
											 CGImageGetColorSpace(image.CGImage),
											 CGImageGetBitmapInfo(image.CGImage));
	CGContextConcatCTM(ctx, transform);
	switch (image.imageOrientation) {
		case UIImageOrientationLeft:
		case UIImageOrientationLeftMirrored:
		case UIImageOrientationRight:
		case UIImageOrientationRightMirrored:
			// Grr...
			CGContextDrawImage(ctx, CGRectMake(0, 0, image.size.height, image.size.width), image.CGImage);
			break;
			
		default:
			CGContextDrawImage(ctx, CGRectMake(0, 0, image.size.width, image.size.height), image.CGImage);
			break;
	}
	
	// And now we just create a new UIImage from the drawing context
	CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
	UIImage *img = [UIImage imageWithCGImage:cgimg];
	CGContextRelease(ctx);
	CGImageRelease(cgimg);
	return img;
}

@end